<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style type="text/css">
        input {
            width: 280px;
            height: 30px;
            background: url("") no-repeat right center;
        }
    </style>
</head>

<body>
    <input type="text" value="请输入关键字">
</body>

</html>